1. Field of the Invention
The invention relates to storage systems.
2. Related Art
A file servers is a computer storage systems that is used to record and retrieve data, in response to requests made by client devices; these client devices are typically coupled to one or more file server using a communication network. The file server receives requests formatted in a file server protocol and following a data storage and retrieval model that is suited to that protocol. (In many circumstances the file server protocol and the data storage and retrieval model are nearly inseparable.)
Because different client devices often use differing data storage and retrieval models, or differing file server protocols, it is desirable for the file server to provide services using a plurality of such models and protocols. One such model is the Unix file system, with the associated NFS (Network File System) protocol. Other file systems include the Windows NT file system, with the associated CIFS (Common Internet File System) protocol.
One problem that has arisen in the art is that certain functions the file server should advantageously perform, such as backup and restore, differ substantially between differing models and protocols. It would be advantageous for the file server to perform these functions for files using either model, while preserving all the information associated with the file in either model. In particular, this poses a problem because some of the metadata associated with files in the Unix file system is not represented in the Windows NT file system.
Accordingly, it would be advantageous to provide a file server that provides for backup and restore of files in a heterogeneous file server environment, in which metadata associated with each file by each model or protocol is preserved across backup and restore operations. This advantage is achieved in an embodiment of the invention in which the file server (a) notes all file attributes associated with each file; (b) records those file attributes in an analogous record on backup using a different model; and (c) restores those file attributes from the analogous record on a restore operation.